Field of the Embodiments of the Present Disclosure
Embodiments of the present disclosure relate generally to audio signal processing and, more specifically, to an approach for detecting alert signals in changing environments.
Description of the Related Art
Headphones, earphones, earbuds, and other personal listening devices are commonly used by individuals who desire to listen to sounds generated from a particular type of audio source, such as music, speech, or movie soundtracks, without disturbing other people in the nearby vicinity. These types of sounds are referred to herein generally as “entertainment” signals, and each such entertainment signal is characterized herein as an audio signal that is present over a sustained period of time.
Typically, personal listening devices include an audio plug for insertion into an audio output of an audio playback device. The audio plug connects to a cable that carries the audio signal from the audio playback device to the personal listening device. In order to provide high quality audio, such personal listening devices usually include speaker components that cover the entire ear or completely seal the ear canal. The personal listening device is designed to provide a good acoustic seal, thereby reducing audio signal leakage and improving the quality of the listener experience, particularly with respect to bass responses.
One drawback of the above personal listening device design is that, because the devices form a good acoustic seal with the ear, the ability of the user to hear environmental sound is substantially reduced, which can present substantial safety issues for the user. For example, the user may be unable to hear certain important sounds from the environment, such as the sound of an oncoming vehicle, human speech, or an alarm. These types of important sounds emanating from the environment are referred to herein as “priority” or “alert” signals, and each such signal is typically characterized as an audio signal that is intermittent, acting as an interruption to the more sustained sounds generated by entertainment signals or other aspects of the listening environment.
One approach to solving above problem involves attempting to detect alert signals present in the listening environment using one or more microphones that are integrated within a listening device. Upon detecting an alert signal, the listening device can automatically reduce the sound level of an entertainment signal, for example, and playback the alert signal to the user to make the user aware of the alert signal. Traditional solutions for detecting alert signals, however, are computationally complex and require significant processing resources to obtain acceptable performance. Also, such solutions do not consider changing acoustic environments and thus do not provide satisfactory performance in different acoustic environments.
As the foregoing illustrates, more effective techniques for detecting alert signals within listening environments that can be implemented in personal listening devices would be useful.